OBJECTIVES: Few contemporary long bone non-union analyses have been documented. Our study was designed to provide a current understanding of non-union rates and risk factors for long bone fractures.

METHODS: Patients within IBM® MarketScan® Commercial Claims and Encounters database with long bone (femur, humerus or tibia) fracture and surgical repair in the inpatient setting, from Q4 2015 to most recent, were identified. Exclusion criteria included: polytrauma and amputation at index. Outcomes included diagnosis of non-union in the 24-months post-index, concurrent infection, and reoperation. Variables included age, gender, comorbidities, fracture characteristics and severity. Descriptive analyses were performed on all three cohorts. Crude and adjusted rates of non-union (using Poisson regressions with log link) and risk ratios (RR) were estimated with 95% confidence intervals.

RESULTS: 12,770, 13,504 and 4,805 patients with femoral, tibial or humeral surgically-treated fractures were identified [(average age: 36-44, average Elixhauser Comorbidity Index (ECI): 1.04 (standard deviation (SD): 1.60) (tibia) to 1.61 (SD: 2.20) (femur)]. Shaft fractures affected 37.9% (femur), 40.2% (humerus) and 57.1% (tibia) cases, > 74% of all fractures were displaced, 18-27% were comminuted. For femur fractures, 2.7% were Gustilo Type III versus < 1% for humerus fracture and 9.7% for tibial fractures. The cumulative hazard for non-union at the 24-months post-surgery time point reached 8.5% (8.0%-9.1%), 9.1% (8.6%-9.7%) and 7.2% (6.4%-8.1%) in the femoral, tibial and humeral fracture cohorts, respectively. Complex fractures (open vs closed, Gustilo III vs Gustilo I-II) also increased risk for non-union (RR for Gustilo III fracture (vs closed) for femur: 1.96 (1.47-2.61), for tibia: 3.33 (2.85-3.87), risk ratio for open (vs closed) for humerus: 1.74 (1.30-2.33). Risk ratios associated with patient comorbidities were lower than those related to fracture location or complexity.

CONCLUSIONS: Non-union post-fracture repair surgery is not uncommon with the greatest risk factor related to the severity and clinical presentation of the fracture.